Changes in the Environment

(events related to Earth science)

Global WarmingGlobal Warming – is the increase of Earth’s

average surface temperature due to effect of greenhouse gases, such as carbon dioxide emissions from burning fossil fuel or from deforestation which trap heat that would otherwise escape from Earth.

- ecological and social changes on Earth

Effects of Global WarmingWeatherIce sheets and GlaciersSea levelAgriculturePlants and AnimalsHuman Health

WeatherSome experts predict that an

increase in global warming will result in unpredictable weather patterns, including storm surges in which wind piles up water in low-lying areas.

Storm Surge Barrier, The Netherlands

Ice sheets and GlaciersSurface temperatures in the Arctic have risen

almost twice as much as the global average. Satellites have made continual observations of Arctic sea ice since 1978. The extent of Arctic sea ice has declined by about 8.5 percent per decade from its size in 1979 (top image). Since 2002 satellite records have revealed unusually early onsets of springtime melting in the areas north of Alaska and Siberia, as well as a smaller recovery of sea ice during the winter season. In 2005 (bottom image) satellites showed the lowest extent of Arctic sea ice on.

Bottom 2005upper 1979

Sea LevelAs the atmosphere warms, the surface

layer of the ocean warms as well, expanding in volume and thus raising sea level.

Sea level rose 10 to 25 cm (4 to 10 in) during the 20th century ( range is due to measurement uncertainties and regional variation.).

By the end of the 21st century, sea level is projected to rise another 28 to 58 cm (11 to 23 in) if greenhouse gas emissions continue to increase significantly

AgricultureGlobal warming of a few degrees

may increase agricultural production, but not necessarily in the same places where crops are grown now.

Plants and AnimalsPlants and animals will find it difficult to

escape from or adjust to the effects of global warming. Scientists have already observed shifts in the lifecycles of many plants and animals, such as flowers blooming earlier and birds hatching earlier in the spring. Many species have begun shifting where they live or their annual migration patterns due to warmer temperatures.

Polar bears and other animals in the polar regions are especially vulnerable to the effects of global warming, such as dwindling sea ice. These animals are uniquely adapted to their environments, and for them migration to other regions is not possible. Animals in warmer regions may shift their ranges toward the poles and to higher elevations as global temperatures increase

Other animals that may extinct soon:

1. Grizzly bears2. Turtles3. Crabs4. Emperor Penguins

Even the entire ecosystem, such as forest may also not be able to survive.

Ocean ecosystem, especially the fragile ones like coral reefs will be also affected by the global warming.

Danger to coral reefsBleach – cause by warmer ocean

temperature which is if prolonged will lead to the death of coral.

Scientists estimate that even 1 Celsius degree (1.8 Fahrenheit degrees) of additional warming could lead to widespread bleaching and death of coral reefs around the world.

Human Health Because of the increase of the temperature diseases such as malaria, dengue fever, yellow fever, encephalitis are expected to spread widely.

Greenhouse EffectGreenhouse effect -

the capacity of certain gases in the atmosphere to trap heat emitted from Earth’s surface, thereby insulating and warming the planet. Without the thermal blanketing of the natural greenhouse effect, Earth’s climate would be about 33°C (about 59°F) cooler—too cold for most living organisms to survive. - warming of Earth’s atmosphere

Types of Greenhouse GasesA. Water Vapor – most common; 60-70% of the

natural greenhouse effectB. Carbon Dioxide – circulates in the environment

through natural process called carbon cycle C. Methane a.k.a natural gas – from

decomposition of carbon containing gasD. Nitrous Oxide – released by the burning of

fossil fuels and automobile exhaustE. Ozone – both natural and human made

greenhouse gasF. Fluorinated Compounds – CFCs and HCFCs

SCARY FACTS!Scientists call this unnatural heating

effect global warming and blame it for an increase in Earth’s surface temperature of about 0.6°C (about 1°F) over the last 100 years. Scientists project global temperatures to continue rising during the 21st century. Warmer temperatures could melt parts of polar ice caps and most mountain glaciers, causing a rise in sea level that would flood coastal regions. Global warming could also affect weather patterns causing, among other problems, prolonged drought or increased flooding in some of the world’s leading agricultural regions.